Rotary pump



- Aug. 4, 1936o 0 H. LAUCHENAUER Filed Sept. 14, 1934 Patented ug. 4, 1936 PATENT OFFICE ROTARY PUMP Hermann Lauchenauer, Zurich, Switzerland, Yassignor tothe rm Maschinenfabrik a. d. Sihl A. G. vorm. A. Schmid, Zurich, Switzerland Application September 14, 1.934, SerialNo. 744,079 In Germany September 20, 1933 4 Claims. (01.1103-111) This invention relates Ato 'rotary pumps particularly for conveying liquids containing coarse im purities, such as sewage, waste-water from factories and the like. l

5 With pumps of this kind, very often interruptions of operation and even defects of the' pump ensue by the foreign matter contained in the liquid, for example large pieces of fibrous materials, such as rags, balls of cotton waste and the like l entering the pump and getting jammed irl-between the induction port face and the vanes of the impeller, so that usually resort' must be taken to stopping the pump plant and demounting the pump for removing the disturbing foreign matter. l .According to the present invention this disadvantage is eliminated in the rotary pump by providing in the induction port face onev or more substantially spiral grooves which increase in depth from the circumference of said face to- 2@ Wards the induction passage, a cutter member being inserted in each groove so as to extend with its cutting edge close to the vanes, for reducing foreign matter such as large pieces of fibrous materials and the like.

25 By virtue of this arrangement foreign matter of this sort is drawn into one of lthe grooves by action of the vane to which it binds, whereby it is torn or cut to pieces on the cutter member or at least stripped off the vane and forced through the o@ groove entirely out of reach of the impeller tothe pressure side thereof to be subsequently removed through'the pressure conduit.

In the accompanying drawing a constructional form of the invention is shown by way of example 35 only, in which Fig. 1 shows an elevation of the port face of the cover of the induction portion of the pump casing, when the cover is viewed from the inside with the vane wheel removed, this wheel being however 40 indicated in dot and dash lines;

Fig. 2 shows an axial section on the line II-II in Fig. 1 the vane wheel being also indicated in dot and dash lines;

Figs. 3 to 5 each show fragmentary sections on 45 the lines. III-III, IV--IV and V-V in Fig. 1 respectively, Fig. 5 being drawn on a reduced scale;

Fig. 6 shows a section on the line VI-VI in Fig. 1 on a larger scale,

Figs. 7 to 9 are views of the cutter head as seen 50 from above, and from two different other sides respectively, and

Fig. 10 shows an axial section through the pump.

In Figs. 1 and 2 of the drawing the cover S of 55 the induction portion of a rotary pump is illustrated to 'be' centrally formed with the suction passage S1. 'I'he inner sideY of the cover `S is formed in a usual manner 'with a conical annular face S2 and the edges R1 of the vanes R of the rotor orimpeller L are parallel to the surface of 5 this annular face. In the conicalfannular face two grooves l are provided in diametrically opposed `relation and extend substantially spirally from the suction passage towards the circumferenceof'the cover of the induction portion of the 10 pump, i. e. the pressure side D (Fig. 10) of the same. vThe depth of these grooves is decreased by .steps from the inner to the outer circumference ofthe annular face which is best `seen by comparing the section shown in Fig. 3 with that 15 shown in Fig. 5, the latter illustrating the normal profile of the annular face S2. The grooves l consist of two main parts, one part having substantially the same outer radius 'as the cutter .2 to be presently described and ending at the latter and merging at said radius into the second part which is shallower and extends radially above the cutter, increasing in width and ending at the periphery of the suction cover. Due to the termination of the first portion of the grooves l at the cutters, it willibe noted that the width of the groove rst 'decreasesv from the suction opening to the point at which the cutter is located then increases from this point to the periphery of the suctioncover. 30

- In each groove l., a cuttermember 2 made kof steel is inserted, the contour of this member being approximately U-shaped in plan i. e. seen in a plane at right angles to the axis of the pump and provided with sides slanting outwardly to- Wards the bottom of the member for engagement in a corresponding recess in the grooves. In the inserted position, the top surface 2a of the cutter member is flush with the annular face S2 of the cover. For connecting the cutter member, 40 a screw 3 with a countersunk head is provided, the recess formed above the head of the screw When screwed home being filled out with metal 4 by soldering or the like. On the side of the cutter member confronting the blades R on their arrival during the rotation of the impeller in the direction of the arrow in Fig. '1, this member is provided with an undercut edge providing a knife 2b. The top surface of the cutter member 2 is flush with the annular face S2, the member projecting beyond the bottom of the groove, and its vertical inner edge 2c is flush with the suction passage S1. Owing to its sides slanting, the cutter mem.- ber 2 is dove-tailed to the cover S and thus pre- 55 vented from dropping off, while the screw 3 keeps the member from shifting radially.

When a rag, a ball of cotton waste or the like enters the pump through the induction passage in the direction of the arrow in Figs. 2 and l0 and binds with the front edge of a vane, this object is forced into one of the grooves I and stripped 01T the vane, when it arrives at the cutter member, and is thereby torn or cut to pieces, whereafter these are further advanced through the respective grooves I to pass into the pressure space D and from thence to the pressure conduit.

Owing to the spiral form of the groove, the foreign matter pressed into the same is conveyed past the longitudinal edges of the groove by the vane, without being severed by the edges of the latter and thereby jammed in, so that no detrimental effect on the pump ensues.

I do not lirnit myself to the particular size, shape, number or arrangement of parts as shown and described, all of which may be varied without going beyond the scope of my invention as shown, described and claimed.

What I claim is:

l. In a rotary suction pump particularly for conveying liquids containing coarse impurities, in combination, a vane wheel rotor, a pump casing having an axial intake and a peripheral outlet, a wall providing a conical annular face in juxtaposition to the vanes of said rotor and having a central inlet opening, at least one substantially spiral, groove provided in said face with the depth thereof increasing from the circumference of said face towards said inlet, a cutter member of a U-shaped contour when seen in a plane at right angles to the axis of the pump inserted in said groove with its top surface flush with said conical annular induction port face, an inner edge of said member situated flush with the wall of said inlet opening, outwardly slanting sides of said cutter member for dove-tailing said member to the adjacent material adjoining said groove, and an undercut knife edge on said cutter member extending close to said vanes, for reducing bulky impurities.

2. In a rotary suction pump particularly for conveying liquids containing coarse impurities in combination, a vane wheel rotor, a pump casing having a center intake and peripheral outlet, a. wall having a conical annular face provided with a central intake opening and disposed in juxtaposition to the vanes of said rotor, at least one substantially spiral groove provided n said face with the depth thereof increasing from the circumference of said face towards said intake opening, a cutter member inserted in said groove with its top surface flush with said conical annular face, a headed screw for fastening said member to said cover passed through said top surface of said member, the recess formed in said face above the head of said screw when screwed home being lled out with metal, and a cutting edge on said cutter member extending close to said vanes, for reducing bulky impurities.

3. In a rotary pump for contaminated liquids, a casing having an annular wall provided with a central suction opening therein, a vane wheel rotor having the vanes thereof operating closely adjacent the inner surface of said wall, said wall having at least one substantially spiral groove formed in its surface and extending from said suction opening to the periphery thereof, each groove being formed by two overlapping, radially inner and outer recesses or groove parts in said wall, said recesses merging with each other radially along their entire overlapped portions, a cutter member mounted in said groove at the overlapped end of the radially inner recess or groove part and having a cutting edge substantially flush with the surface of said wall for reducing bulky matter entrained by said vanes, said inner part of said spiral lgroove guiding bulky matter caught thereby in conjunction with said vanes to said cutter and when reduced toward the periphery of said wall through said outer groove part.

4. In a rotary pump for contaminated liquids, a pump housing, a bladed rotor member Within said housing, one wall of said casing disposed closely adjacent the blades of said rotor having an inlet opening substantially centrally thereof, said wall having a substantially spiral groove formed in the inner face thereof extending from the edge of the inlet opening to the outer radius of the rotor blades, a knife member mounted in said groove having a cutting edge in proximity to the blades of said rotor, the depth of said groove decreasing from the inner to the outer end thereof and the width thereof decreasing from the suction opening to the point at which the knife member is mounted and then increasing from said point to the outer end thereof.

HERMANN LAUCHENAUER. 

